Provided are systems and methods for determining the oil content of wellbore solids. More particularly, systems and methods may be provided for a real-time analysis of the oil in solids that have been recovered from a wellbore.
During the drilling of a wellbore into a subterranean formation, a drilling fluid, also referred to as a drilling mud, may be continuously circulated from the surface down to the bottom of the wellbore being drilled and back to the surface again. The drilling fluid serves several functions, one of them being to transport wellbore cuttings up to the surface where they are separated from the drilling fluid. Additionally, other solids present in the wellbore or added to the drilling fluid may also be transported and/or circulated in and/or out of the wellbore. These solids may comprise an amount of oil, either from the drilling fluid itself or from hydrocarbons native to the wellbore. The oil content of these solids is important for a variety of downstream reasons, such as disposal, efficacy of solids control equipment, etc. For these reasons and others, it may be important to precisely know the oil content of the solids recovered from a wellbore.
Determining the oil content of solids recovered from a wellbore may be useful for an efficient drilling operation. For example, the oil content may allow operators of a drilling operation to determine the method of solids disposal, price of solids disposal, the efficacy of the solids control equipment, changes to the downhole formation, filtration characteristics or requirements, etc. For example, recovered solids comprising a large volume of oil may require expensive disposal methods since the amount of oil which may be disposed of may be regulated. As another example, solids comprising a large volume of oil, may indicate that the solids control equipment is not performing in a sufficient manner. A correctly used and maintained solids control system may be necessary to maintain the drilling fluid which ensures that additional recovered solids, such as drill cuttings, make it to the surface.
Typically, the oil content of recovered solids has been measured using a technique called a retort. A retort uses a distillation unit to heat and then distill the oil in a recovered solid. The volume fraction may then be compared to a baseline if known or used to establish a baseline. This process can take an hour or more. As such, the retort process is slower to perform and may provide measurements that lag relative to the operation. The retort measurements only illustrate the oil content of the solid when the sample was taken. This may lead to delayed correction of an errant process and a reduction in the overall efficiency of the operation.